The invention relates to a plug connection for a welding muff and an electrically welding plastic sleeve having on the inside of a sleeve member an electrical resistance heating wire whose end sections are formed over support members into contacts.
Various methods are known for the production of electrically welding plastic sleeves with which it is possible to produce a connection between sections of pipes and/or shaped members and fittings by heating the joint by electrical resistance heating. The welding sleeves have a sleeve member in the inside of which is appropriately embedded the electrical resistance heating wire necessary for heating purposes. The sleeve member can either be constructed as a one-part tubular member or as a multipart member whose individual parts are produced successively.
In order to connect the resistance heating wire of such a welding sleeve with a power supply, there are provided on the outside of the sleeve connections, particularly plug and socket connections, which on the one hand bring about a satisfactory electrical contact and on the other provide reliable protection against electric shocks. In general, the manufacture of such plug and socket connections constitutes an expensive operation in the manufacture of the welded sleeve. Separate parts used for the plug and socket connection must be connected with the resistance heating wire, or the ends of the wire can be passed through the sleeve member and shaped in an appropriate manner to form an element of a plug and socket connection, e.g. a contact pin or stud. Difficulties are encountered in inserting the ends of the coiled resistance heating wire through to the outside of the sleeve member, due to inadequate supporting or guidance of the end of the wire.
It would be desirable to so further develop a plug connection and welding muff of the type indicated hereinbefore so that it is possible to produce the welding sleeve, and in particular its electrical connections, with limited expenditure and reliable guidance of the end of the wire.